(CHILIAN EAGLE.)
+Haliaëtus melanoleucus+, _Burm. La-Plata Reise_, ii. p. 435 (Paraná,
Tucuman, Pampas). +Geranoaëtus melanoleucus+, _Scl. et Salv.
Nomencl._ p. 119; _Hudson, P. Z. S._ 1872, p. 536 (Rio Negro);
_Durnford, Ibis_, 1877, p. 38, et 1878, p. 397 (Patagonia);
_Gibson, Ibis_, 1879, p. 409 (Buenos Ayres); _Barrows, Auk_,
1884, p. 110 (Entrerios and Ventana). +Buteo melanoleucus+,
_Sharpe, Cat. B._ i. p. 168.
_Description._--Above black, wings grey, with narrow transverse
black bars; tail black: beneath, throat grey; breast black, with
slight round whitish spots; abdomen white, faintly barred across
with grey; bill plumbeous; feet yellow, claws black: whole length
26·0 inches, wing 19·0, tail 10·5. _Female_ similar, but larger.
_Hab._ Whole southern half of South America, and western portion of
northern half.
The Grey or Chilian Eagle, like most diurnal birds of prey, undergoes
many changes of colour, the plumage at different periods having its
brown, black, and grey stages: in the old birds it is a uniform clear
grey, and the under surface white. Throughout the Argentine country
this is the commonest Eagle, and I found it very abundant in Patagonia.
D'Orbigny describes it with his usual prolixity--pardonably so in this
case, however, the bird being one of the very few species with which he
appears to have become familiar from personal observation. He says that
it is a wary bird; pairs for life, the male and female never being found
far apart; and that it soars in circles with a flight resembling that
of a Vulture, and that the form of its broad blunt wings increases its
resemblance to that bird. Cavies and small mammals are its usual prey;
and in the autumn and winter, when the Pigeons congregate in large
numbers, it follows their movements. During the Pigeon-season, he has
counted as many as thirty Eagles in the course of a three leagues' ride;
and he has frequently seen an Eagle swoop down into a cloud of Pigeons,
and invariably reappear with one struggling in its talons. It is seldom
found far from the shores of the sea or of some large river; and on the
Atlantic coast, in Patagonia, it soars above the sands at ebb-tide,
looking out for stranded fish, carcases of seals, and other animal food
left by the retiring waters, and quarrels with Condors and Vultures
over the refuse, even when it is quite putrid. It acts as a weather
prognostic, and before a storm is seen to rise in circles to a vast
height in the air, uttering piercing screams, which may be heard after
it has quite disappeared from sight.
The nest of this species is usually built on the ledge of an
inaccessible rock or precipice, but not unfrequently on a tree. Mr.
Gibson describes one, which he found on the top of a thorn-tree, as a
structure of large sticks three feet in diameter, the hollow cushioned
with dry grass. It contained two eggs, dull white, marked with pale
reddish blotches.
Mr. Gibson compares its cry to a "wild human laugh," and also
writes:--"Its whereabouts may often be detected by an attendant flock
of Caranchos (_Polyborus tharus_), particularly in the case of a young
bird. As soon as it rises from the ground or from a tree, these begin to
persecute it, ascending spirally also, and making dashes at it, while
the Eagle only turns its head watchfully from side to side, the mere
action being sufficient to avert the threatened collision."
Gay, in his 'Natural History of Chili,' describes the affectionate and
amusing habits of an Eagle of this species which he had tamed. It took
great delight in playing with his hand, and would seize and pretend to
bite one of his fingers, but really with as much tenderness as a playful
dog displays when pretending to bite its master. It used also to amuse
itself by picking up a pebble in its beak, and with a jerk of its head
toss it up in the air, then seize it in its claws when it fell, after
which it would repeat the performance.